Music Production

The Audio Series

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RECORDING VOCALS PART 2Selecting a Mic

In part 1 of Recording Vocals, I discussed the importance of finding the best recording space for your vocals. This will support the best tonal quality for the voice. Treating the recording space was the next step discussed, including control of the early reflections that will do the most harm to the tonal quality of the voice.

Once the acoustic space is in order, it is time to set up a microphone and get to recording. Selecting the right microphone also requires a bit of attention and care. The following will help guide you though the process.

Selecting a Mic

Selecting a mic is the next step in getting a great vocal sound. No mic will undo a poor recording space, but once you have established the best recording space, the mic selection will take your sound to the next level.

Microphones are like gloves. There is no one glove that fits everybody perfectly. There are some microphones that are exceptionally good at capturing most people's voices, but every person's voice is still unique. Unless you happen to own one of these very rare microphones, it must be selected uniquely for each person.

I've always found the best results were gained by setting up as many microphones as I felt might work for the voice I was going to record. Aside from the time it takes to set up the microphones, it doesn't actually take a lot of time to pick one.

How to Pick the Best Mic

Start by recording a vocal line with each mic. The vocalist should sing a line or two from the song that you're going to be recording. One of the mics will to stand out beyond the others in terms of imaging and tonal quality. If there is a significant change in the vocal range later in the song, it may be worth recording that as well to make sure the mic can maintain the sound.

It is typical that tube mics and condenser mics are selected most often for recording vocals because they give the most clarity. With voices that are very bright, a dynamic mic can also come in very handy. Dynamic mics can cut away some of the harshness of a voice and add some warmth and body when needed.

It important not to rule out a mic because of its type or price tag. The most important part of recording vocals is getting the sound you're looking for no matter how you have to get it. If you need to, make the test blind so that you are not swayed by preconceived notions of quality.

Pop Filters

One of the many technical issues with recording vocals is plosives. A plosive is puff of air that is sometimes emanated by the vocalist when singing words that contain the letter P. This puff of air can strike the diaphragm of the microphone with enough force that it causes a low frequency pop or distortion.

A pop filter, or pop screen, can be used to break up the puff of air while still allowing the sound to pass through to the microphone. If you don't have a pop filter handy, another way of getting rid of plosives is by taping a sharpie to the front of the microphone. It should go right down the center of the diaphragm. The sharpie will spread the air out around the diaphragm without really affecting the frequency response.

Pop filters can serve a second valuable purpose even if there's not a big plosive problem with your vocalist. A pop filter also allows you to set a distance from the microphone to which the vocalist can easily and consistently return. It is very important to keep a vocalist singing at an even distance from the microphone.

The distance is important for creating a consistency in terms of frequency response and tonal characteristic. If the vocalist is pulling away or moving around or turning their head when singing then will not be singing directly into the diaphragm. The result is variations in the tonal quality of the voice.

Mic Placement

The real issue with microphone placement for recording vocals is a matter of comfort for the vocalist. If the microphone setup feels obstructive to the vocalist it will take way from their performance. Doing everything possible to make the artist comfortable will always yield the best results.

The primary focus of your setup will be to make sure that the vocalist is able to perform comfortably with good posture. The professional method of recording vocals involves the use of a big boom stand. The boom stand is set up out of the way to the left or right of the vocalist.

The boom stand extends above the head of the vocalist and drops the mic from above down in front of the mouth of the vocalist. This typically works very well because it keeps the microphone out of the way and allows the vocalist to maintain good posture.

As a general rule, the artist should never be seated when recording vocals. If standing is a problem for the artist, then the next best option is to use a stool. This way, they are at least mostly standing up. This can also be handy if you have a long session planned and want to keep the vocalist fresh.

Lyric Sheets

There is one issue that often arises when the microphone is coming from above the head of the vocalist. If the vocalist needs to look at a lyric sheet, the microphone is directly in the way of their sight line. What happens is that the lyrics will either be placed to the left of the right of the microphone. This naturally leads the vocalist to turn away from the mic and not directly into it when they look at the lyrics.

There are 2 ways to deal with this issue when recording vocals using lyric sheets. One way is to set up a mic stand so the microphone can be flipped upside down and come up from below the head, not above. This way they can look straight over the top of the microphone to see the lyrics. As the singer looks at the lyrics they are actually leaning into the microphone not looking away from it. The pop screen will help to keep them at the exact distance you want them to be from the front of the microphone.

Sometimes it is best to set up a vocal mic coming from the side if you have a quality heavy duty mic stand that can handle the weight of a good microphone. The benefit of this setup comes when using tube mics. The tubes will generate heat that naturally goes up towards the diaphragm if set upside down as in the previous example.

This can negatively affect the quality of the sound because the diaphragm will be heated and expand thus changing its performance characteristics. Using a side position will allow the vocalist to see the lyrics and sing directly into the microphone while also keeping the heat from affecting the sound.

Mic Settings

There may be a series of options on your vocal microphone that will help control the sound quality when recording vocals. These options vary from mic to mic, but here is a list of the most common ones found on quality vocal mics.

Polar Pattern

Filters (EQ)

Pads

Polar Pattern:

The polar pattern of a microphone determines the direction from which the microphone is most sensitive to sound sources. The selection of the polar pattern will also determine from what direction, if any, the mic will reject signals.

When recording a single vocalist, the pattern is typically set to cardiod.The cardiod pattern will, to greater or lesser degrees, reject signals from all directions except from directly in front of the mic. This polar pattern is most suitable for recording a single vocalist.

When recording two vocalists with at the same time one mic, a figure 8 pattern will allow equal sensitivity from both the front and back of the mic while rejecting sounds from the sides. This pattern makes recording more comfortable because they do not have to crowd around the front of the mic.

When recording a group of vocalists through one mic, it is typical that the omnidirectional polar pattern is selected. the selection of omni enables equal sensitivity from all directions. This allows the vocalists to comfortably sing toward the mic from every direction.

Filters (EQ):

Filters are a very powerful equalization tool used to eliminate problematic frequencies that are not a necessary part of the sound source. There are 3 basic types of filters, High Pass, Low Pass and Notch. While all three types are helpful, only the high pass filter type is used for recording vocals. It is the only type you will typically find on a mic.

Many large diaphragm microphones use a High Pass (low cut) filter because of their increased sensitivity to low frequencies. This allows the engineer to dramatically remove low frequency rumble that can be caused by air conditioning systems and poor acoustic isolation. Some have selectable frequencies but most are fixed to a single frequency below which signals are cut.

The quality of these filters vary with the quality of the mic and it is common for many mic preamps and audio interfaces to include a High Pass (low cut) filter. Check to see which sounds best without affecting the quality of the vocal recording. If the low frequency rumble in a room is excessive, it may be necessary to use both if there is no way to eliminate the source of the rumble.

Pads:

A pad allows the electronics of the microphone to be buffered from sound sources that create high sound pressure levels. This does not necessarily mean that you won't get distortion as the diaphragm of the mic may not be able to handle the excessive sound pressure levels. If this is the case the mic will need to moved farther from the sound source.

For most vocalists a pad is not necessary, and it is often better to back the vocalist away from the mic if they project too loudly. This is a very common practice when recording opera singers that are trained to project with enough power to fill an opera house.

Moving on:

Up to this point that we have covered the basic principles for getting a great vocal sound. In part 1 we discussed finding the best space for recording vocals and treating that space acoustically to control the tonal coloration of early reflections.

In part 2 we discussed techniques for selecting the microphone that best suits a particular vocalist. The setup of that microphone was also discussed in detail including the use of pop filters to control plosives. Additionally, we discussed the importance of selecting the right polar pattern and using filters and pads to hone in the cleanest sound.

In parts 3 and 4 of Recording Vocals we will discuss recording equipment and techniques that are used on the other side of the glass. The use of mic preamps, compression and EQ will be discussed in detail. I will also discuss the importance of creating a good headphone mix and some tips to help the vocalist keep good pitch. Additionally, I will take a look at recording vocals through buss powered interfaces and the many issues you will encounter.